using System;
public class Program
{
public static void Main()
int first = 100;
int second = 200;
Console.WriteLine("Before Swap: first: " + first + " second: " + second );
swap(ref first, ref second);
Console.WriteLine("first: " + first + " second: " + second );
}
public static void swap(ref int first, ref int second)
first = first + second;
second = first - second;
first = first - second;